1. Field of the Invention
The present disclosure relates to a vehicle-mounted device including an input device connected to a device compatible with a predetermined interface standard such as HDMI (registered trademark) (High Definition Multimedia Interface) and inputting a digital content from the device and an output unit connected to a device compatible with the predetermined interface standard and outputting a digital content to the device, and a device authentication method for a vehicle-mounted system including the vehicle-mounted device.
2. Description of the Related Art
A vehicle-mounted system including a digital television tuner, display monitors provided for a front seat and a back seat, and a navigation apparatus has been suggested (JP 2008-211338 A). In this vehicle-mounted system, in accordance with a command from the navigation apparatus serving as a system master in the vehicle-mounted system, a digital television tuner serving as a source device authenticates the navigation apparatus as an authentic repeater device and authenticates the display monitor, which is to display a digital video content, as an authentic sink device. After the authentication, a digital video content which is output from the digital television tuner serving as the source device is relayed by the navigation apparatus serving as the repeater device and is distributed to the display monitor serving as the sink device, so that the display monitor displays the digital video content which is output from the digital television tuner.
In the vehicle-mounted system described in JP 2008-211338 A, when the display monitor to which the digital video content is to be output (on which the digital video content is to be displayed) is changed (change of the distribution path), e.g., when the state is changed from a state in which the digital video content is distributed to both of the display monitors for the front and back seats to a state in which the digital video content is distributed to only the display monitor for the front seat, the distribution of the digital video content from the digital television tuner is stopped temporarily on the basis of the command from the navigation apparatus, and the changed display monitor is authenticated as the authentic sink device. Therefore, in JP 2008-211338 A, the video of the display monitor which is commonly used before and after the change (the display monitor for the front seat in the example) temporarily blacks out, and the problem that this causes the users to feel annoyed has been identified.
Also, a vehicle-mounted system is known which includes a vehicle-mounted device including an input unit connected to a device compatible with the HDMI (High Definition Multimedia Interface) and inputting a digital content from the device and an output unit connected to a device compatible with the HDMI and outputting a digital content to the device. In such vehicle-mounted system, when a first device compatible with the HDMI (for example, a display device provided for the back seat) is connected to the output unit of the vehicle-mounted device, and the second device compatible with the HDMI (for example, a smartphone) is connected to the input unit of the vehicle-mounted device, then, the first device is authenticated as a sink device, the second device is authenticated as a source device, and the vehicle-mounted device is authenticated as a repeater device. For example, when the output unit of the vehicle-mounted device outputs a digital video content to the first device (the display device provided for the back seat) and the second device (smartphone) is connected to the input unit of the vehicle-mounted device while the digital video content is being output (displayed) from the first device, the output of the digital video content from the output unit of the vehicle-mounted device to the first device is temporarily interrupted when the vehicle-mounted device, the first device, and second device authenticate the vehicle-mounted device as a repeater device, and this causes the output (for example, display) of the digital content of the first device to be temporarily stopped (for example, the video temporarily blacks out), and the same problem as the problem associated with the system described in JP 2008-211338 A may occur. More specifically, the problem that the users feel annoyed may occur.
The present invention is made in view of such circumstances, and embodiments of the present invention provide a vehicle-mounted device capable of making it less likely for the user to feel annoyed about a change in the output of a connected device due to authentication processing. In addition, embodiments of the present invention provide a device authentication method in a vehicle-mounted system including the vehicle-mounted device.